Fossils of ancient sea creature discovered

Toronto researchers make 500-million-year-old find in Tulip Beds in Canadian Rockies

Reconstruction of Siphusauctum gregarium. The animals are shown in life position, standing upright in the water column partially anchored into the sediment by a small holdfast. (Copyright Marianne Collins/ROM/U of T/PLoS One)

Canadian researchers have discovered a bizarre flower-like creature which lived in an ancient sea that covered part of Western Canada more than 500 million years ago.

The find, published Wednesday in the science journal PLoS One, is based on more than 1,100 fossil specimens from a new locality in the famous Middle Cambrian Burgess Shale, nicknamed the Tulip Beds, situated in the Canadian Rockies.

Officially named Siphusauctum gregarium, the tulip-shaped creature is about 20 centimetres long and has a unique filter feeding system. It lived in large clusters as indicated by slabs containing over 65 individual specimens.

Researchers from the University of Toronto and the Royal Ontario Museum describe Siphusauctum as having a long stem, with a calyx – a bulbous cup-like structure – near the top that encloses a filter feeding system and a gut. The animal likely fed by filtering particles from water actively pumped into its calyx through small holes. The stem ends with a small disc that anchored the animal to the seafloor.

"Most interesting is that this feeding system appears to be unique among animals. Recent advances have linked many bizarre Burgess Shale animals as primitive members of many animal groups that are found today but Siphusauctum defies this trend. We do not know where it fits in relation to other organisms," said lead author Lorna O’Brien, a PhD candidate in the Department of Ecology and Evolutionary Biology at the University of Toronto.

The Tulip Beds, located in Yoho National Park, British Columbia, were first discovered in 1983 by the Royal Ontario Museum. Set high on Mount Stephen, overlooking the town of Field, the Beds represent rock layers with exceptional preservation of mostly soft-bodied organisms.

The Burgess Shale preserves fossil evidence of some of the earliest complex animals that lived in the planet's oceans nearly 505 million years ago. and the discovery of Siphusauctum expands on the range of animal diversity that existed during this time period.

The area is protected under the larger Rocky Mountain Parks UNESCO World Heritage site and managed by Parks Canada.